A hydraulic cylinder used for a hydraulic excavator or the like is generally provided with a cushion mechanism for decelerating a piston rod by generating a cushion pressure in the vicinity of a stroke end of the piston rod.
As this type of hydraulic cylinders, JP2001-82415A discloses a hydraulic cylinder in which a passage 15 extending from a working chamber 9 toward a port 11 and a reducing hole 18 allowing an opening portion 17 and the passage 15 to communicate and playing a role of limiting a flow rate of a working fluid in the working chamber 9 and discharging it toward a port 11 are formed in a fitting portion 3 of a first covering member 2 closing an end-surface opening by covering a cylinder tube 1, and a cushion ring 19 is provided on the piston rod 6 adjacent to the piston 5. The cushion ring 19 plays a role of closing a diameter-enlarged hole 13a when the piston rod 6 moves to a direction of discharging the working fluid in the working chamber 9 by being fitted in the diameter-enlarged hole 13a in the vicinity of its movement end. As a result, the working fluid in the working chamber 9 is discharged toward the port 11 via the reducing hole 18 from the opening portion 17 while its flow rate is limited, and a cushion action is applied at the movement end of the piston rod 6.